Core Component 1 provides instrumental support and technical expertise for quantitative and qualitative analyses and for controlled exposure of cell cultures to nitric oxide. This includes automated quantitation of nitrate and nitrite, GC-MS and LC-MS characterization and quantitation of deaminated bases, ethenoadenine, 8- oxoG, spirodiiminohydantoin, nitroimidazole, guanidinohydantoin, oxazolone, nitrotyrosine, and dityrosine. Major equipment includes four mass spectrometers, i.e., an Applied Biosystems API 3000 tandem quadrupole instrument, and Applied Biosystems Voyager Elite DE MALDI-TOF instrument, an Agilent MSD trap, and an Agilent 5973N GC-MS (shared with Prof. Dedon). The tandem quadrupole and the ion trap are used primarily as LC-MS instruments and are equipped with a variety of ion sources including standard electrospray, atmospheric-pressure chemical ionization, and nanoelectrospray/microelectrospray. An accelerator mass spectrometer is available for quantitation of low levels of 14C. Other equipment includes standard and capillary liquid chromatographs with detection by UV, diode-array, fluorescence, and laser-induced fluorescence, shared modular autoinjectors and thermostatted column compartments. The Core also includes cell-culture facilities with a new electronically controlled gas mixing system for delivery of nitric oxide and other gases. Objectives for the Core include specific needs of the Projects and enhancement of overall Core capabilities.: Aim 1: develop or improve analytical methods required for individual Program Projects; Aim 2: develop a capillary scale automated desalting or 2D chromatographic systems; Aim 3: complete a high-speed fiber-optics network with a customized protein database software package (MASCOT); Aim 4: evaluate photoionization and atmospheric-pressure ion sources for the ion-trap mass spectrometer with respect to selectivity and sensitivity for analytes of interest to the Program.